An integral image, also referred to as a summed area table, is a table or block of sums where each sum is associated with a pixel position of an image or a block of pixels on the image. Each sum is a total of pixel values above and to the left of that pixel position and the pixel value at that pixel position. The pixel values may be luminance or chroma components. The integral image is used in various algorithms for video analytics, object identification or motion detection, image processing including smoothening or filtering, and so forth.
For many high traffic video coding systems, it is efficient to have the integral image available for cache. Cache, and other types of memory, receive and store blocks of data called cachelines. The cache, however, has a limited capacity, and the integral image may use more bandwidth on the cachelines than is necessary, which reduces the hit rate for other data.